The present invention relates to a gear pump of the type having two rotors, with the shaft of at least one rotor being slidably disposed.
For slidably disposed gear pumps, particularly for Newtonian and intrinsically viscous media, the storage temperature represents a rotational-speed-limiting and therefore throughput-limiting quantity. This is particularly true when the slide bearing is pumping-medium-lubricated. As a rule, this is counteracted by a cooling of the rotor shaft, whereby the operable rotational speed range is expanded. Naturally, it is also possible to cool, instead of the shaft, the slide bearing bush on the pump house side.
However, the problem arises in this case of feeding the coolant flow, or more generally, the tempering medium flow, to the bearing area and removing it again from the bearing area, whether on the shaft side or on the housing side. When the medium is supplied on the housing side, there is the problem that, in the case of bearing bushes, which, for reasons of a simpler axial play adjustment, are arranged within the framework of the manufacturing play relatively loosely in the housing and only in a torsion-resistant manner, the feeding and the removal of the tempering medium must take place by way of tight connection points.
It is an object of the present invention to solve this problem. In the case of a gear pump of the initially mentioned type, this is achieved by means of an arrangement wherein the housing-side slide bearing bush extends in one piece axially to exterior surroundings of the pump and a tempering-medium guiding system is provided in the bearing bush with at least one pair of inlets and outlets which are arranged on the exterior surroundings of the pump.
As a result of the fact that the slide bearing bush extends in one piece axially on or in the surroundings of the pump where the inlets and outlets for a tempering-medium guiding system are provided, the above-mentioned sealing problems are eliminated, and the bearing bushes can be manufactured with respect to the bearing play while following much lower tolerances and therefore at significantly lower prices.
According to especially preferred embodiments, the slide bearing of the pump shaft is pumping-medium-lubricated.
In certain preferred embodiments, the shaft can be guided through the slide bearing into the pump surroundings or the slide bearing bush can be constructed as a closing cover of the shaft bearing bore.
In certain preferred embodiments, the tempering-medium guiding system extends in a meandering fashion along the bearing area of the bearing bush.
Certain preferred embodiments are constructed such that the slidably disposed shaft is guided through into the surroundings and a sealing area, preferably constructed as a labyrinth seal area, adjoins the slide bearing area on the slide bearing bush. In this case, the labyrinth seal may be worked either into the slide bearing bush and/or into the shaft.
In certain preferred embodiments, the slidably disposed shaft is guided through to the outside and preferably merges in one piece into a projecting mounting flange with or without a passage bore for the shaft.
So that, in the case of a pumping-medium-lubricated slide bearing, the lubricating flow can be returned into the pumping current of the gear pump, an essentially radially directed bore is provided through the bush and is connected with the delivery space of the pump in preferred embodiments of the invention.
In most cases, not only one of the rotors is slidably disposed on one side as indicated, but both rotors, at least on one side. Normally, the rotors will be slidably disposed on both sides in the same manner. In this case, it is suggested according to preferred embodiments that, at least on one side, both shafts of the rotors are disposed in one of the above-mentioned bearing bushes respectively which mutually secure one another with respect to torsion.
If the slide bearings are pumping-medium-lubricated, the above-mentioned return bores, which are directed essentially radially through the bearing bushes, are provided according to preferred embodiments on the two bearing bushes in such a manner that they lead into one another and communicate jointly with the pump delivery space. In especially preferred embodiments an arrangement is provided, wherein the two bearing bushes rest against one another along essentially plane, axially parallel surfaces between the shafts and the essentially axially parallel conduit to the pump delivery space is formed by grooves which are each machined into the surfaces.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.